leavitt



' F. M. LEAVITT. .AUTOMOBILE TORPEDO. APPLICATION FILED APR .22, I916- RENEWED MAY 23,.19I9.

INVENTOR aw h? gem- ZZY",

Patented July 1, 1919. 2 SHEETS-SHEET I By Attorneys,

WITNESSES: f'

Patented July 1, 1919.

2 SHEETS-SHEET 2- INVE NTOR aruA/y k 711. fnaumz f,

WITNESSES:

By Attorneys,

UNITED STATES PATENT o ruoE.

FRANK M. LEAVITT, OF SMITHTOWN, NEW YORK, ASSIGNOR TO E. WFIBLISS COMPANY,

OF BROOKLYN, NEW YORK, A CORPORATION OF WEST VIRGINIA.

Specification of Letters Patent.

V AUTOMOBILE 'ronrrmo.

Patented July 1, 1919.

' Application filed April 22, 1916, Serial No. 92,869. Renewed May 23, 1919. Serial No. 299,381.

To all whom it may concern:

Be it known that I, FRANK M. LEAVITT, a.

has apparently reached its practical limit with a speed of about knots at a normal range. It is highly desirable to increase the speed in order that the object aimed at may have less time forescape by moving out of the course of the torpedo or out of range. High speed is also very important in a stern chase, for which purpose torpedoes are now available only against comparatively low speed ships. Aspeed of 15 wso knots is highly .desirable.

Another desideratum of great importance is the attainment of precislon of control at high speed.v At present, as the speed approaches the maximum irregularities or eccentricities ofoperation are introduced, which seriously afl'ect, and at times -incapacitate, either the depth gear or the gyroscopicsteering mechanism, or both, so that the torpedo is liable to execute erratic movements.

The present invention provides a torpedo of novel cross-section. The'torpedo has two air flasks, preferably cylindrical, placed either side by side or one above the other, with tangent plates bridging over the cavities between them. The result is an approximately elliptical cross-sec'tion which is.

continued forward in the head and aft the after-body and tail section, so that these also have approximately elliptical cross-sections. The motor mechanism is preferably duplicated, the twin shafts being extended in the plane of the major axis of the torpedo and the respective twin propellers displaced to opposite sides of the central axis of the torpedo, so that they operate on water somewhat removed from the hull, as in the case of twin screws of ordinaryships, and hence with greater propulsive effect and with less rolling tendency.

' The new construction, as compared with existing torpedoes, carries twice the quanhigher speed and tity of compressed air, and with twice the quantlty of fuel and withthe motor or turbine suitably proportioned, develops twice.

the propulsive energy. If the resistance to be overcome were increased in this same proportion, sult from the increased power and size; but

no material advantage would reby reason of the new contour the wetted surface instead of being doubled, is increased only about 126 times that of a torpedo having a single air flask of. the same size and otherwise of normal proportions.

In proportion whereby the speed is considerably increased. The new proportions also result in' a marked diminution of the drag and other disturbto the propulsive energy the resistance is thus diminished about 87%,

ances due to cavitation, as will be explained hereinafter.

In the following descrlption it will be assumed that the two air flasks are placed one proportions,

Figure 1 is a side, elevation,

vertical mid section;

Fig. 2 is a plan, partly broken away, 1n horizontal section mainly in Fig. 3 is a transverse section through the air flasks, in the plane of the line 3-3 in Fig. 1

.Fig. 4 is a transverse section in the plane of the line H in Fig. 1, and showing the motor mechanism;

Fig. 5 is a stern elevatlo'n.

Fig. Bis a diagrammatic plan ofan ordi-- heretofore constructed, and

nary torpedo as Fig. 7 is a similar trating the torpedo provided by invention. r Referring to the drawin s, 'A is the torpedo hull as a Whole,this hull being bullt up of sections somewhat as usual, including the head 13, air flask section 0, the afterbody D and the tail section carrying the propellers, which, as a whole, is indicated by E. These respective sections are com-- monly united detachably in some suitable manner, a construction which may converiently be followed in this improved torpe o.

The flask section C is made up of two air flasks, C C shown as placed one above diagrammatic plan lllusthe present able construction for which is shown in Fig.

3. 'lhese bridge bars may be suitably spaced so-as to connect the respective flasks with the requisite strength. The hull is carried across between the laterally salient portions of the respective flasks by means of plates G, (l, which are preferably flat and which tangent the'circles forming the exteriors of the respective flasks, as clearly shown in Fig. 3. There are thus formed two 'approximately triangular chambers H, H between the air flasks and on opposite sides, it being a function of the hull plates G, G to isolate these chambers from the exterior water and thereby reduce the wetted surface which generates skin friction when the torpedo is in motion.

Each of the air flasks is, or may be, of precisely the same construction as has heretofore been usual. From the air outlet opening (1- of each air flask there leads a tube 7), which. tubes unite and lead to a starting valve 0 of any usual construction, which is connected to, and operated by, the usual starting hook (I in any usual or suitable way. From the valve w the compressed air passes successively through two reducing valves 0 and f. and from the latter, whereby it is reduced to approximately the working pressure, it .is led by a tube g to the usual coni bust-ion chamber or heater [1, and thence by a.

pipe 2' to the nozzle j of the usual turbine I (or any other suitable motor engine) for driving the torpedo. For maintaining com- 'bustion in the heater /zliquid fuel is fed from any suitable fuel reservoir is which re.- ceives air under pressure at its upper side from the tube 9, and the fuel flows therefrom through a tube 7 to the usual fuel inlet of the heater.

In the construction shown the turbine I is of the same construction as that shown in U. S. patent to F. C. B. Page, No. 1,155,435, dated October 5, 1915, to which reference may be made for a full description thereof and of the connected gearing.

The turbine shaft m is extended above and below the turbine wheels and carries pinions n, n and p, p. The pinions 71 mesh with gear wheels'q, the )inions 12 mesh with idler pinions 1", r, whici in'turn mesh with gear wheels q, q. The gearing ratio is such'that the gears 1 q" of each set of gears turn in opposite directions at precisely like speeds.

These gears carry bevel pinions which drive screws,

K. K. The inner propeller shafts which are extended within the shafts J, and which consequently are not shown, carry as usual the aftpropeller screws L, L. This arrangenient differs from the usual one solely in that the gearing group is duplicated. as also are the respective propeller shafts and screws. The shafts J J extend parallel with each other and with the central axis of the torpedo, and are sufficiently far apart to give room for the upper and Lower propeller screws to turn wholly outside of the torpedo hull. The aft ends of the propeller shafts are carried in suitable out-board bearings 11, a, such as are used for suppoitiug twin screw propeller-s on ships, these bearings being mounted on brackets M, M which are extended beyond the bearings and terminate in guiding slides N, N which are designed to move in suitable guides in the launchinf tube. The brackets M, M act also as fins to steady the torpedo and resist rolling.

The exhaust air from the turbine passes mainly through a central exhaust conduit 1 and escapes through the us'ual'seavalve Q. into the tail sect-ion, whence it is discharged at the tail of the torpedo through a discharge conduit P. v This discharge conduit is extended to a point aft of the propeller and is of flattened cross-section where it projects between the screws. as

shown in Fig. 5, and serves thus the double purpose of discharging spent air and of forming a partition between the upper and lower screws, whiclrhas the function of. preventing interference between thecurrents of water created by the respective screws.

The steering of the torpedo is performed in the same manner as heretofore by the usual depth mechanism or diving gear, and the usual gyroscopic steering means; The depth mechanism comprises the usual pendulum It and the usual hydrostat R and depth engine S, the plunger of the latter being connected as usual through the tiller rod 40 to the tiller of the depth-rudder T. The vertical rudders U for steering in the horizontal plane are operated in the usual way from a gyroscopic steering mechanism. These mechanisms are essentially of the usual construction. such as shown in detail in U. S. Patents Nos. 1,080,116, dated December 2. 1913, 1,148,155, dated July 27, 1915, and 1,153,678, dated September 14, 1915. The hydrostat casing V may be advantageously extended athwartships as shown.

In the construction shownthe bridge bars F, F are attached by bolts or other suitable means to the respective air flasks C and for this purpose the flasks are formed with internal bosses a, a to receive the bolts or other fastenings. The bars F ,F are ribbed on their inner sides for strength. and are flattened on their outer faces to afford a seat for the hull plates G, Gwhich are fastened to them and to the flasks in any suitable way, as by riveting or welding. The chambers H, H may be filled with any suitable liquid if ballast is required, or if not, may be filled with air or other gas.

With an ordinary torpedo having a single cylindrical air flask, this flask forms throughout its length the hull or shell of the torpedo and determines the outlines of the head and. after-body, both of which are of circular cross-section at all points. With the improved torpedo having two air flasks, assuming these-to be of the same size as heretofore, 'the crosssection is increased to double that of a single flaslgplus the area of the two chambers H, H; but the perimeter which determines the wetted surface, and hence the skin friction, is increased in much smaller proportion. The perimeter equals the circumference of one flask plus twice the distance between centers. the stored energy is doubled the perimeter is only about 1.66 times the circumference of a single flask, and the total wetted surface and consequent skin friction are increased in a somewhat smaller proportion, viz., by 1.26. Thus, by proportioning the turbine to receive twice the volume of air at the same working pressure as heretofore, it. delivers,

to each group of gearing and to each pair of propeller screws, the same propulsive energy as has heretoforebeen imparted in the ordinary torpedoes to one pair of propeller screws. It results that the propulsive energy of the torpedo is doubled, while its skin friction is increased only about 1.26 times. In addition, the lateral after-body lines are much finer than in the'case of a torpedo with a smgle flask. Furthermore,

body.

the propeller screws act to greater advantage because they are removed from the hull of the torpedo at the tail section and consequently turn in comparatively undisturbed water, or, in other words, act upon solid water so-called. By reason of these several Thus, while differences the new torpedo is capable of a marked increase of speed as compared with torpedoes heretofore made, and underlike conditions of air-pressure, fuel feed and gear ratios.

When a submerged body is moving through the water it parts the water at its advancing or bow end and the water flows in behind it at its following or stern end. The latter operation is facilitated by giving the'stern portion of the body a very gradual taper, so that this portion or afterbody falls in no faster than the inertia of the water will enable it to follow in stream lines.. If the body moves through the water more rapidly than the water can flow in behind it, a cavity is left in the wake of the This phenomenon is technically. known as cavitation. In the ease of a torpedo cavitation becomesv important when pedo to roll.

traveling at high 5 eed. With atorpedo the I cavity, instead of )eing a vacuum, 15 likely to contain air, either rarefied or possibly even under pressure, the presence of air being due to leakage of the exhaust air from the motor through joints in the hull or around the propeller shafts; and because of this introduction of air into the cavity -the latter becomes larger than if it were a vacuum, so that cavitation troubles in a torpedo are liable to become serlous. Fig. 6 illustrates a serious case of torpedo cavltation, the 4 dotted line w-w indicating approximately the boundary of the cavity.

Cavitation involves that the propeller screws-instead'of turning effectively in solidwater, turn partially in the cavity, and to increasing slip, and even below that speed in traversing the curved course for an angle fire cavitation introduces difliculty because it imbalances the propellers, so that a greater depth of blade is efiective on one side than on the other.- Thisis because in traversing a curved coursethe cavitation follows this curve so that the propeller blades on the outer, sides of the curve are working in solid water while those on the inner side are working in'air. As the cavity, whether the course e straight or curved, tapers aft, it follows that the forward propeller screw turns in a larger cavity than the aft one, so that the latter becomes the more effective and has atendency to cause the tortofore apparent only durin angle fire. At

higher speed the same di culty would be encountered when on a straight course. This rollingtendency is highly disadvantageous because it tends to inca acitate the steering mechanisms; if the rolling reached 90 the vertical rudders would become horizontal and the horizontal rudders would become vertical, so that the steering control nechanisms would become wholly inefi' ive and highly erratic movements would r sult; and any degree of rolling tends propdrtionately to approach this condition. Precision in a torpedo is dependent upon maintaining the most effective steering control, and this involves avoidance of any material rolling.

Ileretofore to avoid rolling on a curved courseit has, been found necessary to alterthe pitch of one screw so as to partially b'alvance their efficiency on a curved course;

but this has the disadvantage of oppositely affecting their relative efliciency on a This tendency/has been here straight course, or at lower speed where less cavitation exists. Cavitation also limits speed, because the higher the speed the longer the cavity, and hence the shorter the effective tip portions .of the blades, which alone turn in solid water; hence, as speed is increased screw efiiciency is diminished until a point is reached beyond which no acceleration is possible. Approaching this limit the irregular action due to rolling becomes so marked that the torpedo executes prohibitively erratic movements.

The improved torpedo provided by the present invention largely avoids the disadvantages due to cavitation by reason of the relatively narrower or flatter contour of the after-body, which thus'falls in more gradually in proportion than with the torpedoes heretofore used; and because also of thepropeller screw axes being located as remotely as possible from the-torpedo axis, so that these screws turn outside the hull where they act mainly outside the region of cavitation. Rolling troubles are diminished also because of the non-coincidence of the screw axes with the torpedo axis, so that the propeller screws are less effective to roll the torpedo, even if unbalanced. The propellers are removed so far from the center of the torpedo that it would probably'be practical to use a single upper propeller and a single lower propeller turning in opposite directions.

An important advantage of the invention is that the shape of the war head is altered, so that for the same cubical contents the massof explosive is brought closer to the target, whereby the explosion is given a greater destructive efiect. This is dueto the doubling of the width (height) of the war head adjacent the air -flasks, whereby the forward projection of the war head may bediminished. Because of this the air flasks"( for a torpedo of given length) are displaced forward to the extent shown by comparing Fig. 6, which illustrates the ordinary single flask torpedo, and Fig. 7 which shows in plan the.

new doubleflask torpedo. This forward displacement of the heavy air flasks carries the center of gravity farther forward and en ables the displacement of the after-body to be diminished by reducing the cross-section of the hull at all points between a transverse] plane slightly aft of the flasks and a trans verse plane slightly forward of the screws. It thus results that the after-body has much finer lines than have heretofore been possible. It is in large part to this change that the diminution in cavitation is due.

' With this new torpedo, while with the air flasks of a givensize the propulsive power is doubled, the total displacement is less than double because although the motor weight due to the gearing, shafts and propellers is doubled the motor itself, and the valve group and control mechanisms are not doubled, be-

ing of practically the same weight as in a single flask torpedo. This difference contribute to finer after-body lines and permits higher speed, while din'iinishing the cavitation.

As above indicated, one of the most serious disadvantages of cavitation in a torpedo is that a large proportion of the area of the propeller screws is rendered ineffective by acting upon air or foam instead of upon socalled solid water. ,0, attain high speed it is requisite that a sutticient area of the propellers shall act against substantially unyielding water to enable the engine to exert through the propellers the backward thrust against the .water which corresponds tosuch speed. The present invention attains higher speed principally by making the propeller more effective, and this is due in part to the diminution of cavitation by reason of the changes above described, and in part to the location of the propellers on axes as remote as practicable from the central. longitudinal axis of the torpedo, so that as much of the area of the propellers as possible is brought outside the region of cavltation.

It must not be inferred from the detailed V description of the accompanying drawings hereinbefore given that the invention is necessarily limited to the constructional features and details set forth, as it is susceptible of a considerable range of modification. As above stated, the const-ructionmay be modified to locate the two air flasks side by side instead of one above the other, which involves merely a re-arrangement of the control mechanism; also, from each pair of propeller screws one screw may be omitted, together with its connected shaft and gearing, so as to reduce the screws to one above and one beneath, turning in contrary directions. Other possible modifications will be apparent to those skilled in the art.

I claim as my 'invention:

1. An automobile torpedo having two elongated cylindrical parallel longitudinal air flasks forming part of the transverse contour of the torpedo hull, and comprising PI'OPUI", sive mechanism driven by air supplied from both flasks. V

2. An automobile torpedo having two parallel air flasks, and means for bridging the cavities between them whereby to afford a continuous hull surface of substantially minimum perimetraldimensions.

3. A11 automobile torpedo having two parallel air flasks, and substantially flat hull parallel and longitudinally of the torpedo and forming part of the main hull, such hull being flattened and conforming mainly to Y the flask in transverse contour, and the head and tail of the hull extended beyond the flask and flattened ilrrroiifiil'iliity to the in- "termediate hull portion,

6. An automobile torpedo having a flattened hull, comprising two parallel air flasks forming part of such hull, and having propeller screws turning on axes on opposite sides of the central torpedo axis, said axes coinciding with the axes of the flasks, and intervening motor mechanism for driving such screws.

and propeller screws turning on axes coinciding with the axes of said flasks, and driven respectively from said motor.

8. An automoblle torpedo having a fiattened hull, comprising two pa 'allel cylindrical air flasks, forming part of such hull, a. single motor receiving air from both flasks, and two pairs of propeller screws, the respective pairs turning on axes coinciding with the axes of the respective flasks, with interposed gearing whereby the screws of each pair turn in opposite directions.

9. An automobile torpedo having a flattened hull. and comprising two parallel c 'lindrical air flasks, forming part of the hull of the torpedo, screw propellers on axes coinciding with the axes of the flasks, a motor for driving said propellers, and air connections from both flasks to such motor.

' FRANK M. LEAVITT.

Witnesses CHAS. J. ELLSWORTH, FRED. H. MGGAHIE. 

